photographerswilldecidetousethefastandveryefficient
auto-focusing (AF) options. However there are a few
options andconsiderations thatneedtobe understoodto
get the best outcome from these.
The photographer must realize that although the focus
systemisvery sophisticateditisnotfoolproof. Focusing
systemsworkbyseeinglightanddarkbetweentwoplanes
andlockintothis;ifthisdistinctionisnotpresent,sayfor
exampleinlowlevelsoflightorwhenthesceneisfairly
flat with no distinguishing features, the system will
struggle.Toillustratethis,trytofocusthecameraonaflat
whitewallorinlowlight,andthelenswilltakeitstimeto
settleonanythingtofocusupon;inthesesituationsitmay
well be prudent to switch to manual focus.
Whenlookingthrough theviewfinder of thecamerathe
photographerwillmost likelysee a gridof redfocusing
points.Thesewilllightupwhentheyhavefocusedinona
subject; with no input from the photographer they will
automatically focus on any point closest to them. The
camerawillhavemaybethreeorfourforhowtousethese
focusingspots.Researchthemandfindoutwhichbestsuits
your method or way of working.